1. Field of the Invention
The present invention is based on U.S. Provisional Application No. 60/027,482, filed Sep. 25, 1996, which is directed to a tire deflating mechanism and method wherein a non-lethal, buried device is capable of deflating pneumatic tires by driving hollow steel spikes through the tire treads of a target vehicle. The method and apparatus uses pyrotechnic gas generators or gunpowder to propel spikes from sheaths through a thin layer of soil and into the tire carcass so as to eliminate the blast effect of conventional anti-vehicle mines so as to be useful for establishing anti-vehicle perimeters around military bases and other sensitive areas. The movement of the spike can be limited by the use of cooperating tubes or pistons forming the support for the spike or by the utilization of a short tether on each spike which limits the range of spikes not encountering the tire, while those that penetrate a tire will be pneumatically released from their connection with a support. Spikes that are tethered are releasable from their tethers by air pressure within the tire in a first embodiment. The present invention permits a spike to be impaled in a tire to separate and rotate with the tire, while those not encountering a tire will pose no danger beyond a distance approximately 6 inches above the ground. The interengaging tubes of the second embodiment versus the utilization of the tethers in the first embodiment serves to reduce the possibility of injuries to bystanders from flying spikes while retaining an effective tire deflating capability.
2. Discussion of the Background
Tire deflating mechanisms are known, for example, from U.S. Pat. No. 5,482,397, the disclosure of which is incorporated by reference, which is directed to a tire deflator and method of deflating a tire of a moving vehicle that includes at least one support mechanism and a spike secured to the at least one support mechanism such that upon the tire of the moving vehicle being penetrated by the spike, both the spike and support mechanism rotate with the tire so as to allow for a rapid air depletion of the tire. The method shown therein includes the steps of securing the spike to the at least one support mechanism, positioning the support mechanism in a roadway and penetrating the tire with a spike such that the spike and support mechanism as an integral unit becomes secured to the tire and rotate with the tire after the tire is penetrated by the spike.
Other arrangements for deflating a tire include deployable vehicle barricades as shown in U.S. Pat. No. 4,577,991 and a retractable barrier strip as shown in U.S. Pat. No. 5,507,588, the disclosure of each of which is also incorporated herein by reference. Another road barrier preventing passage of vehicles is characterized by French Patent 2552793 which comprises a set of retractable spikes mounted on a rotatable shaft underneath the road surface. Such structure is, however, complicated in terms of the number of elements required and the manner of operation thereof which includes the need for a double action jack which operates hydraulically, pneumatically or electrically, and which must be situated in a channel in the ground.